Methods and apparatus for detachably fastening a tool shaft to a tool holder

Abstract

A tool shaft is detachably fastened in a tool holder by means of a plurality of gaskets which are each sandwiched between a pair of press rings. The tool shaft extends through the press rings and gaskets. A screw is provided for compressing the gaskets between the press rings. The gaskets are disposed in recesses of larger volume. The gaskets are nonsymmetrical about the longitudinal axis of the tool shaft. When compressed, the gaskets force the tool shaft laterally against the rings to prevent radial misalignment of the tool shaft.

What is claimed is: 
     
       1. Apparatus comprising a tool holder, a tool shaft, means carried by said tool holder for transmitting torsional movement to said tool shaft, and means for detachably fastening said tool shaft to said tool holder comprising a plurality of gaskets surrounding said tool shaft, and press rings for compressing said gaskets, said gaskets being nonsymmetrical relative to a longitudinal axis of said tool shaft. 
     
     
       2. Apparatus according to claim 1, wherein the gaskets are formed of elastic material and are generally cylindrical with at least one end surface thereof beveled to establish said nonsymmetrical relationship. 
     
     
       3. Apparatus according to claim 1, wherein the press rings comprise a centering ring and a support ring disposed at opposite ends of each gasket. 
     
     
       4. Apparatus according to claim 3, further including a spacer ring disposed between the support rings. 
     
     
       5. Apparatus according to claim 4, including a hollow screw threadable into longitudinal engagement with one of said centering rings for compressing said gaskets. 
     
     
       6. In an apparatus comprising a tool holder, a tool shaft, and means for detachably fastening said tool shaft to said tool holder, said fastening means comprising: rigid press means in said tool holder for receiving said tool shaft,   a gasket disposed in a recess surrounding said tool shaft and positioned for being compressed by inward longitudinal forces imposed on said press means, said gasket, in an uncompressed state, having less volume than said recess so that a portion of said recess is unoccupied, said unoccupied portion being nonsymmetrical relative to a longitudinal axis of said tool shaft,     displaceable means for imposing an inward longitudinal force on said press member to compress said gasket in a manner causing said gasket to occupy said unoccupied and simultaneously urge said tool shaft radially firmly against said press means.   
     
     
       7. Apparatus according to claim 6 wherein said press means comprises a centering ring at one end of said gasket and a support ring at the other end of said gasket, said rings each including an aperture receiving said tool shaft, said recess being defined between said rings and being generally cylindrical and said gasket being generally cylindrical with one end beveled. 
     
     
       8. Apparatus according to claim 7, wherein said displaceable means comprises a hollow screw which receives said tool shaft, said screw being tightenable against one of said rings to compress said gasket. 
     
     
       9. A method for fastening a tool shaft in a tool holder comprising the steps of: positioning a gasket in a recess surrounding said tool shaft, such that a portion of said recess remains unoccupied by said gasket in an uncompressed state of said gasket, and compressing said gasket so that said gasket tends to occupy said unoccupied recess portion in a direction laterally of the longitudinal axis of said tool shaft, to urge said tool shaft firmly against a rigid member in said tool holder.